Question

In a reaction between copper oxide and hydrogen, specify the reduction and oxidation taking place in the reaction.

Answer 1

Definition of oxidation.

It is defined as a chemical process that involves the addition of oxygen or removal of hydrogen from an element or a compound in a reaction.

Addition of oxygen

$$\begin{gathered} 4\mathrm{Fe}+3{\mathrm{O}}_2\to 2{\mathrm{Fe}}_2{\mathrm{O}}_3 \\ \mathrm{iron}\mathrm{oxygen}\mathrm{iron}\mathrm{oxide} \end{gathered}$$

Removal of hydrogen

$$\begin{gathered} {\mathrm{H}}_2\mathrm{S}+{\mathrm{Cl}}_2\to 2\mathrm{HCl}+\mathrm{S} \\ \mathrm{Hydrogen}-\mathrm{Chlorine}\mathrm{Hydrogen}-\mathrm{Sulphur} \\ \mathrm{sulphide}\mathrm{sulphide} \end{gathered}$$

Definition of reduction.

It is the reverse of oxidation. ie. removal of oxygen or the addition of hydrogen to an element or a compound.

Removal of oxygen.

$$\begin{gathered} \mathrm{CuO}+\mathrm{C}\to \mathrm{Cu}+\mathrm{CO} \\ \mathrm{Copper}\mathrm{oxide}\mathrm{carbon}\mathrm{copper}\mathrm{Carbon}\mathrm{monoxide} \end{gathered}$$

Addition of hydrogen.

${\mathrm{N}}_2+3{\mathrm{H}}_2\to 2{\mathrm{NH}}_3$

Redox reaction

When oxidation-reduction takes place simultaneously in a reaction it is called a redox reaction.

$$\begin{gathered} \hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\mathrm{Reduction}(\mathrm{removal}{\mathrm{ofO}}_{2)} \\ \mathrm{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_} \\ \downarrow \downarrow \\ \mathrm{CuO}+{\mathrm{H}}_2\to \mathrm{Cu}+{\mathrm{H}}_2\mathrm{O} \\ \downarrow \mathrm{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_}\uparrow \\ \mathrm{Oxidation}(\mathrm{addition}\mathrm{of}{\mathrm{O}}_2) \end{gathered}$$

When hydrogen passed over heated oxide, copper oxide gets reduced to copper while hydrogen gets oxidised to water.